Raritan head running but filling up with water

[DoorCountyScott]

I have an 88 360 aft cabin with Raritan Electric Heads. They both occasionally have issues with flushing. The macerator runs fine and the water comes in but then the bowl just fills with water while it spins. Sometimes they work perfect but this seems to happen to often lately. I have replaced the joker (duckbill) valves, impellers, blew out vent lines (even disconnected them) and it still happens.

[Viper]

I assume it's a Crown head? If so, have you checked the condition of your discharge impeller, not the one in the raw water pump? It's behind the joker valve in the base housing that the motor and bowl are fastened to. It hooks up to the motor on the opposite side of the pump. I believe you have to remove the large cover plate on the end of the housing opposite the motor/water pump. It's a solid impeller and may be broken or is full of toilet paper or something else preventing it from moving waste. If that's okay, you might have a restriction or clog in the discharge hose. If your tank vent is clogged, and you can't displace the air in the tank, it won't allow anything into the tank. Also check that the port behind the joker valve in the housing is clear and not full of debris.

[DoorCountyScott]

Yes crown head and thanks for the idea, wasn't aware there were 2 impellers and that would make sense that is not working.

[Cooler]

Also, make sure the users are running the flush cycle long enough. Really needs to run a minimum of 8 seconds, or things will clog up a bit. I once had what I thought was a plugged up Crown, and the remedy was for me to hold that button in for a couple of 12 second cycles. Then the macerator cleaned itself out and started to run perfect. Users typically run that flush for a few seconds. Where in Door County are you? er

[DoorCountyScott]

Tried the running the macerator for awhile and all that did was fill the bowl. Took a hint from someone else about closing the raw water intake (since my Crowns do not have an impeller on the discharge) and that seems to be the cure!
We are at Quarterdeck in Sturgeon Bay, we were just in Menominee on the 18th we were on the wall near the harbor master.

[Viper]

I don't know that closing the intake is the "cure." If the discharge impeller inside the unit (which you DO have) is working properly and you don't have any restrictions in the system, the discharge impeller should have no problem keeping up with the raw water pump's output and emptying the bowl of its contents. Having to shut off the intake to get it to empty the bowl is just an indication that there's an issue with the discharge system. Do you also have an overboard discharge system with a separate macerator?

[DoorCountyScott]

I don't have my schematic with me, but there was one like the one you posted in my manual then another one with a note that this was the head(s) in this boat and it shows a intake impeller but not a discharge. Each head goes into it's own tank which were both filling up quickly since we were flushing so much water each time.

[Viper]

Check out the head in this manual. Is this not the one you have (Raritan Crown)?...
https://www.raritaneng.com/uploads/L91v0720vCrownHead-49944458.pdf
if it is, look at the diagram...CH119MW is the discharge impeller I'm referring to. It's a solid impeller, not a rubber one.

[DoorCountyScott]

Yes that is my head...are you saying part # CH121 is an impeller? G13W is the intake that I replaced earlier this year. Still working like a champ with the intake valve shut part way!

[Viper]

Source of the post.....CH119MW is the discharge impeller I'm referring to. It's a solid impeller, not a rubber one.